Stator assembly and torque measuring device

ABSTRACT

Disclosed are a stator assembly and a torque assembly device. The stator assembly includes a stator holder, a first stator which includes a first body making contact with an upper end of the stator holder and a plurality of first teeth extending from the first body so as to be disposed inside the stator holder, a second stator which includes a second body making contact with a lower end of the stator holder and a plurality of second teeth extending from the second body so to be alternately aligned with the first teeth inside the stator holder, and a fusion-welded material that is fusion-welded to the stator holder and the first and second bodies.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/742,708, filed Jan. 16, 2013, which is a continuation of U.S.application Ser. No. 12/677,466, filed Mar. 10, 2010, now U.S. Pat. No.8,375,810, issued Feb. 19, 2013, which is the U.S. national stageapplication of International Patent Application No. PCT/KR2008/005352,filed Sep. 10, 2008, which claims priority to Korean Patent ApplicationNo. 20-2007-0015057, filed Sep. 10, 2007, all of which are incorporatedherein by reference in their entirety.

TECHNICAL FIELD

The present embodiment relates to a stator assembly and a torquemeasuring device.

BACKGROUND ART

Since great frictional resistance is applied to a front wheel serving asa steering wheel, a power steering system provides assistant steeringforce to allow a driver to smoothly manipulate a steering handle. Theassistant steering force is determined by measuring torque applied to atorsion bar when the steering handle is steered.

In order to measure torque of the steering wheel, various torquemeasuring devices have been developed and used. Among them, a torquemeasuring device employing a magnetic field has been mainly used sinceit has advantages in terms of a number of parts and price.

In the torque measuring device employing the magnetic field, a magnet iscoupled to a steering handle that is an input shaft, one side of astator holder fixing a stator is coupled to the input shaft through thetorsion bar, and the other side of the stator holder is coupled to anoutput shaft of a front wheel.

Accordingly, when rotating the steering handle by applying externalforce to the steering handle, torque is measured by detecting a magneticfield according to a difference between a rotational angle of the magnetcoupled to the input shaft and a rotational angle of the stator coupledto the stator holder to rotate together with the output shaft. Theassistant steering force is determined based on the measured torque anda motor is driven according to the assistant steering force.

DISCLOSURE OF INVENTION Technical Problem

The embodiment provides a stator assembly and a torque measuring device.

The embodiment also provides a stator assembly, in which a stator can bestrongly coupled to a stator holder, and a torque measuring deviceemploying the stator assembly.

The embodiment provides a stator assembly, in which a stator can beeasily coupled to a stator holder, and a torque measuring deviceemploying the stator assembly.

Technical Solution

According to the embodiment, a stator assembly includes a stator holder,a first stator which includes a first body making contact with an upperend of the stator holder and a plurality of first teeth extending fromthe first body so as to be disposed inside the stator holder, a secondstator which includes a second body making contact with a lower end ofthe stator holder and a plurality of second teeth extending from thesecond body so to be alternately aligned with the first teeth inside thestator holder, and a fusion-welded material that is fusion-welded to thestator holder and the first and second bodies.

According to the embodiment, a stator assembly includes a stator holder,a first stator which includes a first body making contact with an upperend of the stator holder, a plurality of first teeth extending from thefirst body so as to be disposed inside the stator holder, and a firstcoupling rim extending from the first body so as to be coupled to afirst outer portion of the stator holder, and a second stator whichincludes a second body making contact with a lower end of the statorholder, a plurality of second teeth extending from the second body so tobe alternately aligned with the first teeth inside the stator holder,and a second coupling rim extending from the second body so as to becoupled to a second outer portion of the stator holder.

According to the embodiment, a torque measuring device includes a case,a magnet disposed in the case, the magnet being coupled to an inputshaft rotated by external force so as to be rotated, a stator assemblydisposed in the case to surround the magnet, the stator assembly beingcoupled to an output shaft connected to the input shaft through atorsion bar so as to be rotated, and a sensor which detects variation ofa magnetic field generated between the magnet and the stator assembly.The stator assembly includes a stator holder, a first stator whichincludes a first body making contact with an upper end of the statorholder and a plurality of first teeth extending from the first body soas to be disposed inside the stator holder, a second stator whichincludes a second body making contact with a lower end of the statorholder and a plurality of second teeth extending from the second body soas to be alternately aligned with the first teeth inside the statorholder, and a fusion-welded material that is fusion-welded to the statorholder and the first and second bodies.

According to the embodiment, a torque measuring device includes a case,a magnet disposed in the case, the magnet being coupled to an inputshaft rotated by external force so as to be rotated, a stator assemblydisposed in the case to surround the magnet, the stator assembly beingcoupled to an output shaft connected to the input shaft through atorsion bar so as to be rotated, and a sensor which detects variation ofa magnetic field generated between the magnet and the stator assembly.The stator assembly includes a stator holder, a first stator whichincludes a first body making contact with an upper end of the statorholder, a plurality of first teeth extending from the first body so asto be disposed inside the stator holder, and a first coupling rimextending from the first body so as to be coupled to a first outside ofthe stator holder, and a second stator which includes a second bodymaking contact with a lower end of the stator holder, a plurality ofsecond teeth extending from the second body so as to be alternatelyaligned with the first teeth inside the stator holder, and a secondcoupling rim extending from the second body so as to be coupled to asecond outside of the stator holder.

Advantageous Effects

According to the embodiments, a stator assembly and a torque measuringdevice can be provided.

According to the embodiments, a stator assembly, in which a stator isstrongly coupled to a stator holder, and a torque measuring deviceemploying the stator assembly can be provided.

According to the embodiments, a stator assembly, in which a stator iseasily coupled to a stator holder, and a torque measuring deviceemploying the stator assembly can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 are views showing a stator assembly and a torque measuringdevice according to a first embodiment;

FIG. 3 is a view showing a stator assembly and a torque measuring deviceaccording to a second embodiment;

FIG. 4 is a view showing a stator assembly and a torque measuring deviceaccording to a third embodiment;

FIG. 5 is a view showing a stator assembly and a torque measuring deviceaccording to a fourth embodiment;

FIG. 6 is a view showing a stator assembly and a torque measuring deviceaccording to a fifth embodiment;

FIG. 7 is a view showing a stator assembly and a torque measuring deviceaccording to a sixth embodiment; and

FIG. 8 is a view showing a stator assembly and a torque measuring deviceaccording to a seventh embodiment.

MODE FOR THE INVENTION

Hereinafter, a stator assembly and a torque measuring device accordingto embodiments will be described with reference to accompanyingdrawings.

Hereinafter, details about a stator assembly and a torque measuringdevice adaptable for a power steering system for a vehicle will be madeaccording to the embodiments.

First Embodiment

FIG. 1 is a perspective view showing a stator assembly and a torquemeasuring device according to a first embodiment.

As shown in FIG. 1, a case 110 is prepared with a predetermined innerspace. The case 110 includes an upper case 111 and a lower case 115, inwhich the upper case 111 is provided at an upper portion of a virtualvertical line, and the lower case 115 is provided at a lower portion ofthe virtual vertical line. The upper case 111 is formed at a centralportion thereof with a through hole 112, and the lower case 110 isformed at a central portion thereof with a through hole (not shown)corresponding to the through hole 112.

Hereinafter, a surface facing an upper portion of the virtual verticalline will be referred to as a top surface, and a surface facing a lowerportion of the virtual vertical line will be referred to as a bottomsurface.

A stator holder 210 having a cylindrical shape is installed on the lowercase 115, and stators 310 are coupled to upper and lower ends of thestator holder 210.

The stator 310 is provided at an inside thereof with a magnet 120 havinga ring shape, which has a plurality of polarities radially aligned. Themagnet 120 is provided at an inside thereof with a magnet holder 130.The magnet 120 has an inner circumferential surface coupled with anouter circumferential surface of the magnet holder 130 having acylindrical shape, and the outer circumferential surface of the magnet120 faces teeth 313 of the stator 310, which will be described later,with a predetermined interval.

An input shaft (not shown), which is a steering shaft penetrating thethrough hole 112 of the upper case 111, is fitted into the innercircumferential surface of the magnet holder 130, and an output shaft(not shown) linked with a front wheel of a vehicle, which is a steeringwheel, is fitted into the stator holder 210.

In detail, the stator holder 210 is formed with a connection part 211having a ring shape which extends radially inward. The connection part211 is formed with an insertion hole 212. The output shaft (not shown)linked with the front wheel of the vehicle (which is the steering wheel)is inserted into the insertion hole 212 while penetrating the throughhole of the lower case 115. A steering handle is coupled to the inputshaft, and the input shaft is coupled to the output shaft through atorsion bar (not shown).

Therefore, when rotating the steering handle by applying an externalforce to the steering handle, the input shaft is rotated, and the magnetholder 130 and the magnet 120 are rotated similarly to the input shaft.Then, the output shaft receives a rotational force of the input shaftthrough the torsion bar to rotate, and the stator holder 210 and thestator 310 rotate similarly to the output shaft.

However, since the output shaft is coupled to the front wheel in thecontact with a road, torque occurs in the torsion bar due to frictionalresistance between the road and the front wheel. The magnet 120 rotatesat a rotational angle different from that of the stator 310 due to thetorque of the torsion bar, a magnetic field between the magnet 120 andthe stator 310 varies due to difference between rotational angles of themagnet 120 and the stator.

The magnetic field generated from the magnet 120 and the stator 310 isdetected by a sensor 140 supported on a circuit board 141 of the lowercase 115. Accordingly, a controller (not shown) receives the intensityof the magnetic field detected by the sensor 140 and compares thereceived intensity of the magnetic field with a preset value to measurethe torque. Then, the controller determines assistant steering forcerequired to steer a vehicle based on the measured torque and drive amotor to provide the assistant steering force.

A reference number 150 which is not described represents a collector toconcentrate a magnetic field such that the sensor 140 can effectivelydetect the intensity of the magnetic field. Meanwhile, in order toexactly measure a magnetic field, the stator 310 coupled to the statorholder 210 must not move on the stator holder 210.

In the torque measuring device according to the present embodiment, thestator 310 is directly coupled to the stator holder 210 with solidity.This will described later with reference to FIGS. 1 and 2. FIG. 2 is aperspective view showing the stator 310 and the stator holder 210 shownin FIG. 1.

As shown in FIG. 2, the stator holder 210 has a cylindrical shape, andis provided at a lower end thereof with the connection part 211 and theinsertion hole 212. The output shaft is inserted into the insertion hole212.

The stators 310 include bodies 311 having a ring shape and a pluralityof teeth 313 which are bent from the inner circumferential surface ofthe bodies 311 and spaced apart from each other by a predeterminedinterval. The bodies 311 of the stators 310 make contact with upper andlower ends of the stator holder 210. The teeth 313 are provided into thestator holder 210 to make contact with an inner circumferential surfaceof the stator holder 210.

The teeth 313 of the stator 310 coupled to an upper portion of thestator holder 210 are alternately aligned with the teeth 313 of thestator 310 coupled to a lower portion of the stator holder 210.

The teeth 313 of the stator 310 coupled to the lower portion of thestator holder 210 penetrate a communication hole 211 a formed in theconnection part 211 such that the teeth 313 are provided inside thestator holder 210. The teeth 313 face the outer circumferential surfaceof the magnet 120.

In order to couple the stator 310 to the stator holder 210, a pluralityof protrusions 213 that can be fusion-welded by heat or an ultrasonicwave are formed on the upper and lower ends of the stator holder 210with a predetermined interval. The protrusion 213 makes contact withboth side surface of each tooth 313 of the stator 310. In detail, afterinserting the stator 310 into the stator holder 210 such that theprotrusion 213 makes contact with both side surface of each tooth 313 ofthe stator 310, the protrusion 213 is fused by heat or an ultrasonicwave. Accordingly, since a portion of the fused protrusion 213 coversthe tooth 313, the stator 310 is strongly fusion-welded to the statorholder 210.

A plurality of partition grooves 215 are formed on the innercircumferential surface of the stator holder 210 to guide the teeth 313such that the teeth 313 are provided with a predetermined interval. Incontrast, protrusion guides (not shown) may be formed on the innercircumferential surface of the stator holder 210 instead of thepartition grooves 215.

Second Embodiment to Seventh Embodiment

FIGS. 3 to 8 are perspective views showing stators and stator holders ofstator assemblies according to second to seventh embodiments.Hereinafter, only difference between the first embodiment and the secondto seventh embodiments will be described in order to avoid redundancy.

As shown in FIG. 3, in a torque measuring device according to the secondembodiment, stators 320 have bodies 321 formed thereon with couplingholes 321 a, and a stator holder 220 is formed on upper and lower endsthereof with a plurality of protrusions 223 which are inserted into thecoupling holes 321 a and fused by heat or a ultrasonic wave. Theprotrusions 223 are fused by heat or an ultrasonic wave, and a fusedportion of the protrusions 223 cover the body 321 so that the body 321is fusion-welded to the stator holder 220.

As shown in FIG. 4, in a torque measuring device according to the thirdembodiment, protrusion parts 230 a protrude from outer peripheralsurfaces of upper and lower ends of a stator holder 230.

The protrusion 230 a has a ring shape. The protrusion 230 a includes thesame material as that of the stator holder 230, and is integrally formedwith the stator holder 230. In other words, the protrusion part 230 a isinjection-molded together with the stator holder 230 when the statorholder 230 is injection-molded.

Bodies 331 of stators 330 are mounted on the upper and lower ends of thestator holder 230, and an outer circumferential surface of the body 331of the stator 330 makes contact with an inner circumferential surface ofthe protrusion part 230 a. In addition, the protrusion part 230 a has aheight greater than thickness of the body 331 of the stator 330.

Heat or an ultrasonic wave is applied to the protrusion part 230 a suchthat the protrusion part 230 a is fused. Accordingly, a fused portion ofthe protrusion part 230 a covers the body 321 of the stator 330 so thatthe body 321 is fusion-welded with the stator holder 220.

As shown in FIG. 5, a torque measuring device according to the fourthembodiment includes stators 340, bodies 341 making contact with upperand lower ends of a stator holder 240, a plurality of teeth 343 bentfrom an inner circumferential surface of each body 341, and a couplingrim 345 bent from an outer circumferential surface of the body 341 toface an outer circumferential surface of the stator holder 240. Thecoupling rim 345 includes a plurality of caulking parts 345 a so thatthe coupling rim 345 is coupled to the outer circumferential surface ofthe stator holder 240. Accordingly, the stator 340 is strongly coupledto the stator holder 240.

As shown in FIG. 6, in a torque measuring device according to the fifthembodiment, a stator holder 250 includes protrusion rims 255 formed onouter peripheral surfaces of upper and lower ends of the stator holder250.

Similarly to the stator 340 according to the fourth embodiment, stators350 include bodies 351, teeth 353, and coupling rims 355. The bodies 351make contact with the protrusion rims 255 as well as the upper and lowerends of the stator holder 250. In addition, the coupling rim 355 facesan outer circumferential surface of the protrusion rim 255, and includesa plurality of caulking parts 355 a to couple to the protrusion rim 255.

In this case, the coupling rim 355 has a width larger than a thicknessof the protrusion rim 255.

As shown in FIG. 7, a torque measuring device according to the sixthembodiment includes a stator holder 260 having the same structure asthat of the stator holder 250 according to the fifth embodiment.

Stators 360 include bodies 361, which make contact with protrusion rims265, as well as upper and lower ends of the stator holder 260, aplurality of teeth 363 bent from an inner circumferential surface ofeach body 361, and a plurality of coupling protrusions 367 protrudingfrom an outer peripheral surface of the bodies 361. The couplingprotrusion 367 is bent to couple to the protrusion rim 265, so that thestator 360 is coupled to the stator holder 260.

In this case, the coupling protrusion 367 may be formed by partiallydividing the coupling rim 345 shown in FIG. 5 along an outercircumference of the body 341.

As shown in FIG. 8, in a torque measuring device according to theseventh embodiment, a stator holder 270 has a cylindrical shape, andstators 370 have bodies 371 fixed onto upper and lower ends of thestator holder 270 by an adhesive.

In addition, in a torque measuring device according to anotherembodiment, the stator 370 having a shape according to the seventhembodiment may be integrally formed with the stator holder 270 wheninjection-molding the stator holder 270.

As described above, in the torque measuring device according to theembodiments, a stator is directly coupled to a stator holder by aprotrusion of the fusion-welded stator, a portion of the fusion-weldedstator holder, a caulked portion of the stator, or a bent portion of thestator. Accordingly, an additional part to couple the stator to thestator holder is not required, so that the manufacturing cost isreduced.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

INDUSTRIAL APPLICABILITY

The present invention is adaptable for a torque measuring device.

What is claimed is:
 1. A stator assembly, comprising: a stator holder; a first stator comprising a first body having a ring shape and a plurality of first teeth extended from the first body and spaced apart from each other, wherein the plurality of first teeth are coupled to a first portion of the stator holder; and a second stator comprising a second body having a ring shape and a plurality of second teeth extended from the second body and spaced apart from each other, wherein the plurality of second teeth are coupled to a second portion of the stator holder, wherein the stator holder comprises a plurality of protrusions making contact with the first stator and securing the first stator to the stator holder.
 2. The stator assembly according to claim 1, wherein the stator holder further comprises a plurality of communication holes, wherein each second tooth penetrates a communication hole of the plurality of communication holes.
 3. The stator assembly according to claim 2, wherein the stator holder further comprises a connection part having a ring shape which extends radially inward from the stator holder, wherein the plurality of communication holes are formed through the connection part.
 4. The stator assembly according to claim 1, wherein the stator holder further comprises a plurality of partition grooves provided at an inner circumferential surface thereof, wherein each first tooth is disposed in a partition groove of the plurality of partition grooves, and wherein each second tooth is disposed in a partition groove of the plurality of partition grooves.
 5. The stator assembly according to claim 4, wherein the first teeth and the second teeth are disposed in the plurality of partition grooves in an alternating fashion, such that each first tooth is disposed between two second teeth and each second tooth is disposed between two first teeth.
 6. The stator assembly according to claim 1, wherein each first tooth makes contact with an inner circumferential surface of the stator holder, and wherein each second tooth makes contact with the inner circumferential surface of the stator holder.
 7. The stator assembly according to claim 1, wherein each first tooth comprises: a first portion extending radially inward from an inner circumferential surface of the first stator; and a second portion bent from the first portion, and wherein each second tooth comprises: a first portion extending radially inward from an inner circumferential surface of the second stator; and a second portion bent from the first portion.
 8. The stator assembly according to claim 7, wherein the first portion of each first tooth makes contact with a protrusion of the plurality of protrusions of the stator holder.
 9. The stator assembly according to claim 7, wherein the first portion of each first tooth makes contact with two protrusions of the plurality of protrusions of the stator holder.
 10. The stator assembly according to claim 7, wherein the second portion of each first tooth extends away from the first portion of said first tooth in a lower direction, wherein the first portion of each first tooth comprises an upper surface facing an upper direction that is opposite to the lower direction, and wherein the upper surface of the first portion of each first tooth makes contact with two protrusions of the plurality of protrusions of the plurality of protrusions of the stator holder.
 11. The stator assembly according to claim 7, wherein the stator holder further comprises: a connection part having a ring shape which extends radially inward from the stator holder; and a plurality of communication holes formed through the connection part, wherein the second portion of each second tooth penetrates a communication hole of the plurality of communication holes.
 12. A stator assembly, comprising: a stator holder; a first stator comprising a first body having a ring shape and a plurality of first teeth extended from the first body and spaced apart from each other, wherein the plurality of first teeth are coupled to a first portion of the stator holder; and a second stator comprising a second body having a ring shape and a plurality of second teeth extended from the second body and spaced apart from each other, wherein the plurality of second teeth are coupled to a second portion of the stator holder, wherein the stator holder comprises a plurality of communication holes, and wherein each second tooth penetrates a communication hole of the plurality of communication holes.
 13. The stator assembly according to claim 12, wherein the stator holder further comprises a connection part having a ring shape which extends radially inward from the stator holder, wherein the plurality of communication holes are formed through the connection part.
 14. The stator assembly according to claim 13, wherein each first tooth comprises: a first portion extending radially inward from an inner circumferential surface of the first stator; and a second portion bent from the first portion, wherein each second tooth comprises: a first portion extending radially inward from an inner circumferential surface of the second stator; and a second portion bent from the first portion, and wherein the second portion of each second tooth penetrates a communication hole of the plurality of communication holes.
 15. The stator assembly according to claim 12, wherein the stator holder further comprises a plurality of partition grooves provided at an inner circumferential surface thereof, wherein each first tooth is disposed in a partition groove of the plurality of partition grooves, and wherein each second tooth is disposed in a partition groove of the plurality of partition grooves.
 16. The stator assembly according to claim 15, wherein the first teeth and the second teeth are disposed in the plurality of partition grooves in an alternating fashion, such that each first tooth is disposed between two second teeth and each second tooth is disposed between two first teeth.
 17. The stator assembly according to claim 12, wherein each first tooth comprises: a first portion extending radially inward from an inner circumferential surface of the first stator; and a second portion bent from, the first portion, and wherein each second tooth comprises: a first portion extending radially inward from an inner circumferential surface of the second stator; and a second portion bent from the first portion.
 18. The stator assembly according to claim 17, wherein the second portion of each second tooth penetrates a communication hole of the plurality of communication holes. 